Hi Kevin, BenoÃt, On Tue, 16 Nov 2010, Paul Walmsley wrote: > Change the per-hwmod mutex to a spinlock. (The per-hwmod lock > serializes most post-initialization hwmod operations such as enable, > idle, and shutdown.) Spinlocks are needed, because in some cases, > hwmods must be enabled from timer interrupt disabled-context, such as > an ISR. The current use-case that is driving this is the OMAP GPIO > block ISR: it can trigger interrupts even with its clocks disabled, > but these clocks are needed for register accesses in the ISR to succeed. The more I think about this patch, the less I like it. At some point it would be good to try to convert the OMAP clock code to using mutexes in as many places as possible, rather than spinlocks. When that happens, this is going to be a liability. Nevertheless I will leave it this patch in for now by request, but this is just a simultaneous request: as we review these hwmod conversions, we need to be very careful with any code that will attempt to call the hwmod functions from timer-interrupt-disabled context ... we should try to discourage it if at all possible and if that is not possible, to put a big fat XXX comment there to review the situation... - Paul
